In an epic effort to explore and learn as much as possible about the mysterious red planet Mars, the brilliant scientist and engineers working for National Aeronautics and Space Administration (NASA) have so far created and sent four mechanical space explorers- Sojourner, Spirit, Opportunity, and Curiosity to Mars in hopes of better understanding our planet’s neighbor.
Only Opportunity and Curiosity are still functional and continue to explore the Mars’ surface while investigating Martian climate, geology, environmental conditions that favor microbial life including the role of water, as well as the possibility of planetary habitability. Furthermore, Opportunity has successfully completed its 90 day mission and continues to gather data, exceeding its operational plan by 13 years, while Curiosity is still exploring Aeolis Mons (Mount Sharp) located within Gale crater. However, harsh Martian environment is not kind to the rovers and even though they have endured more that it was expected, the red planet’s continuous damage is starting to take its toll.
Hardware vs. Environment
The robotic rover Curiosity was designed to explore the Martian soil, landscape and atmosphere as well as to survive the harsh environmental conditions of the red planet. However, there is so much we still do not know about Mars and those unexpected circumstances may lead to catastrophic consequences. Luckily, Curiosity is still doing its job well, regardless of the damage it withstood on its journey.
Unlike its predecessors, Spirit and Opportunity, that have a solar panel based power source, Curiosity is equipped with radioisotope thermoelectric generator (RTG) that produces electricity from the decay of radioactive isotopes such as plutonium-238 dioxide currently equipped by Curiosity. Heat that is given off by the decay is converted to electricity by thermocouples that provide constant power even during the night. This allows Curiosity to avoid power shortage due to the dust debris that can pile up on solar panels or lack of sunlight. However, the space buggy is enduring other types of damage that can place its mission at risk.
Frequent dust storms and rough terrain filled with sharp rocks are beating the Curiosity hard. As expected, Curiosity was built to withstand punishment from Mars and survive long enough to complete its mission but the harsh environment on Mars is proving difficult to overcome. Back in December 2016, NASA reported that Curiosity did not complete the command for drilling. The most probable cause is either the debris that is preventing the drill arm from fully extending or the drill arm’s motor issue.
The Wheels are Wearing off
The most recent damage to Curiosity was done to its wheels. Curiosity is equipped with six wheels that are 20 inches (50 centimeters) in diameter and 16 inches (40 centimeters) wide, milled out of solid aluminum. The damage dealt to the left-middle wheel is located in raised threads called grousers. The last checkup conducted on January 27th in 2017 showed no damage but the image from March 19 shows two small breaks on the wheel, which makes the scientist believe that the damage has occurred just recently.
Curiosity Project Manager Jim Erickson of NASA’s Jet Propulsion Laboratory, Pasadena, California, said that “All six wheels have more than enough working lifespan remaining to get the vehicle to all destinations planned for the mission.” and that “While not unexpected, this damage is the first sign that the left middle wheel is nearing a wheel-wear milestone”.
However, all the moving parts on Curiosity ranging from wheels to cameras are still intact. They are greased with Castrol industrial lubricant called Castrol Braycote 601 EF specifically designed for the harsh terrain and environment, being able to withstand temperature variations from minus 80 degrees to 204 degrees Celsius.
The monitoring of Curiosity wheel-wear was initiated after holes and dents started appearing much faster than anticipated back in 2013, which forced scientist do drive the rover backwards. Due to the damage to the grousers, the wheel has reached 60 percent of its useful life as Curiosity marks its 10 mile (16km) milestone.
Exploration Continues
Despite the damage, Curiosity continues to explore Mount Sharp and will most likely cover all the destinations intended for its mission. All the information gathered on the Curiosity’s voyage will serve to improve the new rover that will lead the mission to Mars in 2020.